YES, it is Yes, Prime Minster, but then again, no, it isn’t.

What was formerly a sitcom series of snappy half-hour episodes on the Beeb in Thatcher’s Eighties has become a two-hour play, still peopled by the same characters but now transposed on to the modern Britain of the Cameron & Clegg double act.

As in the days of the Paul Eddington-Nigel Hawthorne axis, the writers remain Antony Jay and Jonathan Lynn, whose political satire now walks the 21st century corridors of shared power (although the Coalition is mentioned only in passing).

The play began life as an anniversary production in the West End, went on tour last year when it played Leeds Grand Theatre, and is now doing the rounds again with Graham Seed – Nigel Pargetter in The Archers in a former soap life – in the hot seat as Prime Minister Jim Hacker.

Seed’s Hacker is almost as posh as “Dave” Cameron, and as ever Hacker has an air of hopelessness and bafflement when faced by the fierce intelligence of Michael Simkins’s urbane, superior Cabinet Secretary, Sir Humphrey Appleby.

Sir Humphrey’s withering dissection of the state of Westminster politics is the play’s best moment and it comes right at the start. What follows is a conventional drawing-room farce with a labyrinthine plot and a lot of politics that would have benefited from a further update to reflect 2012 (as confirmed by the mocking laughter that greets the already-in-place reference to dinner with the Prime Minister).

Jay and Lynn set Yes, Prime Minister in a world of 24-hour news channels, Blackberrys and constant mandarin interference over a long weekend at Chequers, where the PM is heading to personal meltdown. In his company are Sir Humphrey, Latin-quoting, long-suffering Principal Private Secretary Bernard Woolley (Clive Hayward) and a savvy female newcomer, unflappable, glamorous Special Policy Advisor Claire Sutton (Polly Maberly).

Hacker’s financially crippled coalition government has been reduced to begging on bended knee to Kumranistan, whose promise of aid to Britain – facilitated by Sir Humphrey – hangs on the procurement of an under-age hooker for this slippery new oil state's Foreign Secretary.

Director Jonathan Lynn’s production becomes too laborious in the first half, as the laughter slows down, especially in the scene with the Kumranistan Ambassador (Sam Dastor), but it has second wind after the interval, when Seed’s Hacker goes up a notch as the PM strives to become more assertive.

The satire is more sophisticated, elegant and less abrasive than the rata-tat-tat attack of Armando Iannucci’s The Thick Of It. It is less physically imposing too, its humour more rooted in the spinning of words, especially in the twisting, turning, obfuscating monologues of Sir Humphrey, which twice drew spontaneous applause at Monday’s press night.

Even in the first-half lull, the writing retains its all-important confidence, indeed bravado, especially in its critique of the editorial policy of the BBC (as represented by Tony Boncza’s frazzled Director-General), and above all in every devious, conniving utterance by Simkins’s Sir Humphrey.

Jay and Lynn manage to stay once step ahead even of him, adding to the pleasure of a satire that is vintage yet modern, sometimes daft but always gently anarchic.

Yes, Prime Minister, York Theatre Royal, until Saturday, 7.30pm plus 2pm, Thursday, and 2.30pm, Saturday. Box office: 01904 623568 or yorktheatreroyal.co.uk